mineral

Yellow Chalcedony

Silicon Dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale), Color: Pale yellow to honey gold, Luster: Waxy to vitreous, Crystal Structure: Trigonal (microcrystalline/cryptocrystalline), Cleavage: None, Specific Gravity: 2.58-2.64

Hardness: 6

Identified July 3, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs scale), Color: Pale yellow to honey gold, Luster: Waxy to vitreous, Crystal Structure: Trigonal (microcrystalline/cryptocrystalline), Cleavage: None, Specific Gravity: 2.58-2.64

Formation & geological history

Forms from the deposition of silica-rich water in cavities and veins within igneous and sedimentary rocks. It often forms at relatively low temperatures.

Uses & applications

Commonly used as a gemstone for cabochons, beads, and carvings. Also used in industrial applications for precision bearings and pivot points due to its toughness.

Geological facts

Chalcedony is a cryptocrystalline form of silica, meaning its crystals are so small they can only be seen under high magnification. Yellow varieties are often associated with sunlight and focus in metaphysical traditions.

Field identification & locations

Look for a translucent to opaque appearance with a waxy luster and no visible crystal faces. It is commonly found in India, Brazil, Madagascar, and the USA (notably in the Southwest).